In the manufacture of upholstered items such as chairs, car seats and the like, many steps are necessary for contouring, fitting, cutting, etc., the outer coverings and final assembly of such items. More recently, ways have been found to reduce the number of manufacturing steps required for producing the outer structures of such items by vacuum forming the textile cover and applying to the back thereof a foamed elastomeric core by, for instance, pouring thereon a liquid foamable polyurethane composition. In such a process, however, the textile cover or laminate is often stretched to as much as 300 percent area increase resulting in an overall thickness of about 0.5 mil. In so doing, minute pin-holes in any part of the textile cover or backing are often enlarged significantly. The liquid foamable compositions have a tendency to seep through the interstices of the fabric to the outer surface causing disruption and discoloration of such surface. Such phenomenon is known as "strike-through", and it has been dealt with in the past by, for instance, applying to the back of the fabric a thin film of thermoplastic material such as nylon or poly(vinyl-chloride). Although "strike-through" was for all practical purposes eliminated, such adhered thermoplastic films give the fabric a boardy and uncomfortable feel, i.e. a poor hand. Many approaches have been tried to avoid the detrimental boardiness characteristic and yet have a laminate that also avoids the "strike-through" phenomenon described above.
German patent publication No. 3230321 (Meiller et al) discloses a padding laminate comprising a fabric to which is attached a foamed lining layer to whose outer surface is applied a foam core. Opposite to the fabric, the lining layer may be singed causing the top layer of the lining layer to melt and be compacted.
U.S. Pat. No.4,353,955 (Cook) describes a method for applying polyurethane foam to a fabric wherein one surface of the fabric is treated with silicone surfactant; subsequently, an expandable polyurethane composition is affixed to the treated fabric surface and then the polyurethane is caused to foam.
U.S. Pat. No. 1,109,381 (Quertain) teaches a laminate structure of a fabric to which is adhered a ca. 2.5 mm thick foam, onto which is attached a thermoplastic film, the latter is held in a vacuum mold.
Canadian Pat. No. 973790 (Phillips) deals with a fabric to which is attached by adhesion a ca. 2 mm polyethylene foam. The laminar structure is then placed, fabric down into a vacuum mold and liquid foamable polyurethane is applied to the polyethylene foam.
U.S. Pat. No. 3,847,720 (Laberints) discloses a foamed polyurethane core and a microporous water proof polyurethane skin, at least a portion of said skin being covered by a fabric.
All of the above methods and laminar constructions realize some improvement in the flexibility of the fabric structures, however, they still provide laminate cushioning having uncomfortable bulkiness or boardiness due to either the necessary thickness of the closed cell foam attached to the fabric--if it were prepared in situ; to the adhesive layer used for the foam-to-fabric attachment; or to the inherent stiffness of the various barrier layers and/or adhesives proposed. As an aside, it is very difficult to generate closed cell foam in thin layers e.g. less than 3 mils to 8 mils in thickness, without realizing a very stiff material, for one needs a very high modulus binder system in the liquid layer to contain the gases being generated and thus maintain the closed cells. In the case of an open cell foam layer adjacent the fabric, it is extremely difficult to apply a liquid foamable composition, such as liquid foamable polyurethane, under vacuum forming conditions without having the inevitable "strike-through" of the polyurethane.